Expandable supportive branched endoluminal grafts

ABSTRACT

An endoluminal graft which is both expandable and supportive is provided in a form suitable for use in a branched body vessel location. The graft expands between a first diameter and a second, larger diameter. The support component is an expandable stent endoprosthesis. A liner is applied to the endoprosthesis in the form of a compliant wall material that is porous and biocompatible in order to allow normal cellular invasion upon implantation, without stenosis, when the expandable and supportive graft is at its second diameter. The supportive endoluminal graft is preferably provided as a plurality of components that are deployed separately at the branching body vessel location, one of which has a longitudinal seam defining leg portions within which the other components fit in a telescoping manner.

CROSS REFERENCE TO RELATED APPLICATION

This is a divisional application of application Ser. No. 09/657,041,filed Sep. 5, 2000, which is a reissue application of U.S. Pat. No.5,855,598 issued Jan. 5, 1999, which is a continuation-in-part ofapplication Ser. No. 08/558,028, filed Nov. 13, 1995, filed Nov. 13,1995, now U.S. Pat. No. 5,632,772 and application Ser. No. 08/558,034,filed Nov. 13, 1995, now U.S. Pat. No. 5,639,278, which are each acontinuation-in-part of application Ser. No. 140,245, filed Oct. 21,1993, now abandoned and is related to divisional reissue applicationSer. No. 10/788,966, filed Feb. 25, 2004, and continuation reissueapplication Ser. No. 11/332,917, filed Jan. 17, 2006.

BACKGROUND AND DESCRIPTION OF THE INVENTION

This invention generally relates to supportive endoluminal grafts whichhave the ability to be delivered transluminally and expanded in place toprovide a graft that is endoluminally positioned and placed, with theaid of an appropriate inserter or catheter, and that remains so placedin order to both repair a vessel defect and provide lasting support atthe location of the graft. In its broadest sense, the graft preferablycombines into a single structure both an expandable luminal prosthesistubular support component and a compliant graft component securedthereto. The expandable supportive endoluminal graft takes on abifurcated or branched structure made up of components that are designedto be positioned in a bifurcated manner with respect to each other,preferably during deployment or repair and support of vessel locationsat or near branching sites. Preferably, the graft component iscompliant, stretchable or elastomeric and does not substantially inhibitexpansion of the tubular support component while simultaneouslyexhibiting porosity which facilitates normal cellular growth or invasionthereinto of tissue from the body passageway after implantation.

Elastomeric vascular grafts are known to be made by various methods.Included are methods which incorporate electrostatic spinning technologysuch as that described by Annis et al. in “An Elastomeric VascularProsthesis”, Trans. Am. Soc. Artif. Intern. Organs, Vol. XXIV, pages209-214 (1978) and in U.S. Pat. No. 4,323,525. Other approaches includeelution of particulate material from tubular sheeting, such as byincorporating salts, sugars, proteins, water-soluble hydrogels, such aspolyvinyl pyrrolidone, polyvinyl alcohol, and the like, within polymersand then eluting the particulate materials by immersion in water orother solvent, thereby forming pores within the polymer. Exemplary inthis regard is U.S. Pat. No. 4,459,252, incorporated by referencehereinto. Another approach involves the forming of pores in polymers byphase inversion techniques wherein a solventized polymer is immersed inanother solvent and the polymer coagulates while the polymer solvent isremoved. Also known are spinning techniques such as those described inU.S. Pat. No. 4,475,972. By that approach, a polymer such as apolyurethane in solution is extruded as fibers from a spinnerette onto arotating mandrel. The spinnerette system reciprocates along a path whichis generally parallel to the longitudinal axis of the mandrel and at acontrolled pitch angle. The result is a non-woven structure where eachfiber layer is bound to the underlying fiber layer.

Also known are stent devices, which are placed or implanted within ablood vessel or other body cavity or vessel for treating occlusions,stenoses, aneurysms, disease, damage or the like within the vessel.These stents are implanted within the vascular system or other system orbody vessel to reinforce collapsing, partially occluded, weakened,diseased, damaged or abnormally dilated sections of the vessel. Attimes, stents are used to treat disease at or near a branch, bifurcationand/or anastomosis. This runs the risk of compromising the degree ofpatency of the primary vessel and/or its branches or bifurcation, whichmay occur as a result of several problems such as displacing diseasedtissue, vessel spasm, dissection with or without intimal flaps,thrombosis and embolism.

One common procedure for implanting a stent is to first open the regionof the vessel with a balloon catheter and then place the stent in aposition that bridges the diseased portion of the vessel. Variousconstructions and designs of stents are known. U.S. Pat. No. 4,140,126describes a technique for positioning an elongated cylindrical stent ata region of an aneurysm to avoid catastrophic failure of the bloodvessel wall, the stent being a cylinder that expands to an implantedconfiguration after insertion with the aid of a catheter. Other suchdevices are illustrated in U.S. Pat. Nos. 4,787,899 and 5,104,399. U.S.Pat. Nos. 4,503,569 and 4,512,338 show spring stents which expand to animplanted configuration with a change in temperature. It is implanted ina coiled configuration and then heated in place to cause the material ofthe spring to expand. Spring-into-place stents are shown in U.S. Pat.No. 4,580,568. U.S. Pat. No. 4,733,665 shows a number of stentconfigurations for implantation with the aid of a balloon catheter. U.S.Pat. No. 5,019,090 shows a generally cylindrical stent formed from awire that is bent into a series of tight turns and then spirally woundabout a cylindrical mandrel to form the stent. When radially outwardlydirected forces are applied to the stent, such as by the balloon of anangioplasty catheter, the sharp bends open up and the stent diameterenlarges. U.S. Pat. No. 4,994,071 describes a bifurcating stent having aplurality of wire loops that are interconnected by an elongated wirebackbone and/or by wire connections and half hitches.

Stents themselves often do not encourage normal cellular invasion andcan lead to undisciplined development of cells in the stent mesh, withrapid development of cellular hyperplasia. Grafts alone do not provideadequate support in certain instances. Copending application ofJean-Pierre Dereume, Ser. No. 08/546,524, entitled “Luminal GraftEndoprostheses and Manufacture Thereof” describes grafts that have theability to carry out dilatation and/or support functions. An expandabletubular support component and an elastomeric graft component arecombined into a single device wherein the graft material is secured toeither or both of the internal and external surfaces of the expandablesupport component. The graft material is produced by a spinningtechnique such as that described in U.S. Pat. No. 4,475,972. Also,luminal endoprostheses with an expandable coating on the surface ofexternal walls of radially expandable tubular supports are proposed inU.S. Pat. Nos. 4,739,762 and 4,776,337. In these two patents, thecoating is made from thin elastic polyurethane, Teflon film or a film ofan inert biocompatible material. A. Balko et al., “TransfemoralPlacement of Intraluminal Polyurethane Prosthesis for Abdominal AorticAneurysm”, Journal of Surgical Research, 40, 305-309, 1986, and U.S.Pat. Nos. 5,019,090 and 5,092,877 mention the possibility to coat stentmaterials with porous or textured surfaces for cellular ingrowth or withnon-thrombogenic agents and/or drugs. The various patents andpublications referred to hereinabove are incorporated hereinto byreference.

By the present invention, grafts which are expandable and supportive areprovided that expand from a first diameter to a second diameter which isgreater than the first. When it is at its first diameter, the expandablesupportive graft is of a size and shape suitable for insertion into thedesired body passageway. The material of the graft is substantiallyinert and preferably has a generally cylindrical cover and/or lininggenerally over the outside and/or inside surface of the expandablesupportive component. Preferably, the cover and/or lining is especiallyadvantageous because it is compliant or elastomeric and porous toencourage desirable growth of tissue thereinto in order to assist innon-rejecting securement into place and avoidance of stenosisdevelopment. The porous liner and/or cover material is compliant orelastomeric enough to allow for expansion by up to about 2 to 4 times ormore of its unexpanded diameter. Components of the branched orbifurcated expandable supportive endoluminal graft preferably aredeployable separately such that each component is properly positionedwith respect to the other into the desired branched or bifurcatedarrangement. One of the components has a portion which has at least onelongitudinally disposed indent to generally define at least two legportions for receiving one of the other components.

It is a general object of the present invention to provide an improvedbranched endoluminal graft that is expandable in place and, onceexpanded, is self-supporting.

Another object of this invention is to provide biocompatible graftshaving a plurality of components that are separately expandable in vivoand that are supportive once so expanded.

Another object of the present invention is to provide an improvedexpandable reinforced graft that is delivered by way of introducers,balloon catheters or similar devices, and which facilitates good tissueingrowth.

Another object of this invention is to provide an improved endoluminalgraft which fully covers diseased or damaged areas for carrying outluminal repairs or treatments, such as repair of aneurysms.

Another object of the present invention is to provide an improvedendoluminal graft wherein the endoprosthesis is substantially enclosedwithin biocompatible compliant material which is presented to thesurrounding tissue and blood or other body fluid.

Another object of this invention is to provide an expandable, supportivegraft that can be tailored to meet a variety of needs, including asingle graft designed to address more than a single objective.

Another object of the present invention is to provide a self-expandingreinforced graft device that is delivered in its elongated andcompressed state from within a tubular member and deployed by movingsame out of the tubular member, which device is especially suitable forcomponent deployment.

Another object of this invention is to provide a bifurcated trunkcomponent that is deployed in a collapsed state and expanded in vivo toa branched device for use in treatment and/or repair at branched vessellocations.

A further object of the present invention is to provide a componentbranched endoluminal graft having a longitudinally creased trunkcomponent and at least one cylindrical branch component, whichcomponents are expanded separately after endoluminal delivery and whichform a bifurcated graft once positioned with respect to each other andexpanded.

Another object of this invention is to provide an improved method offorming a branched endoluminal graft incorporating a longitudinalcreasing procedure.

Another object of the present invention is to provide an improved methodof assembling a branched endoluminal graft.

These and other objects, features and advantages of this invention willbe clearly understood through a consideration of the following detaileddescription.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be further elucidated in the following descriptionwith reference to the drawings, in which:

FIG. 1 is a perspective view, partially cut away, of an expandablesupportive endoluminal graft construction in accordance with theinvention;

FIG. 2 is a cross-sectional view along the line 2-2 of FIG. 1;

FIG. 3 is a perspective view, partially cut away, of another embodimentof the expandable supportive endoluminal graft construction;

FIG. 4 is a cross-sectional view along the line 4-4 of FIG. 3;

FIG. 5 is a perspective view, partially cut away, of a furtherembodiment of the expandable luminal graft construction;

FIG. 6 is a cross-sectional view along the line 6-6 of FIG. 5;

FIG. 7 is a perspective view, partially cut away, of a bifurcatedexpandable supportive endoluminal graft construction;

FIG. 8 is a cross-sectional view along the line 8-8 of FIG. 7;

FIG. 9 is a somewhat schematic view illustrating an early step in theimplantation of a device such as shown in FIG. 7;

FIGS. 10, 11 and 12 are generally schematic views along the lines ofFIG. 9 showing expansion of the main body and the branches of thisbifurcated device;

FIG. 13 shows this bifurcated supportive graft after completion of theexpansion procedure;

FIG. 14 illustrates another embodiment of a bifurcated expandablesupportive endoluminal graft construction;

FIGS. 15, 16 and 17 illustrate implantation and assembly of the graft ofFIG. 14;

FIGS. 18, 19, 20 and 21 illustrate a component branched graft andvarious stages of its separate, component deployment within a bodyvessel to repair an aneurysm, FIGS. 18 and 19 showing deployment of apreferred branched, longitudinally indented trunk component, and

FIGS. 20 and 21 showing separate deployment of two branch componentswithin the trunk component;

FIG. 22 is a top plan view of an embodiment of a branching trunkcomponent in accordance with the invention;

FIG. 23 is a cross-sectional view along the line 23-23 of FIG. 22;

FIG. 24 is a side elevational view of the branching trunk component asillustrated in FIGS. 22 and 23;

FIG. 25 is an end view of the structure as shown in FIG. 24;

FIG. 26 is a perspective, generally exploded view of an example of afixture suitable for forming the longitudinal crease in this trunkcomponent;

FIG. 27 is a longitudinal broken-away view of the fixture of FIG. 26with a braided cylindrical tube positioned therein;

FIG. 28 is a view generally in accordance with FIG. 27, showingformation of opposing crease indents in the braided cylindrical tubeduring formation of this trunk component;

FIG. 29 is a top plan view showing assembly of supportive endoprosthesisleg components into a branching trunk component according to theinvention;

FIG. 30 is an end view of the structure as shown in FIG. 29;

FIG. 31 is a perspective view of another embodiment of a branching trunkcomponent in accordance with the invention;

FIG. 32 is a cross-sectional view along the line 32-32 of FIG. 31; and

FIG. 33 is a perspective view of a modified embodiment of a branchingtrunk component, having a section of enhanced hoop strength.

DESCRIPTION OF THE PARTICULAR EMBODIMENTS

An embodiment of expandable supportive luminal graft construction isgenerally illustrated in FIG. 1 at 21. This embodiment includes abraided tubular support component having generally helically wound rigidbut flexible strand or wire elements, some of which have the samedirection of winding but are axially displaced from one another, andothers of which cross these windings and are also axially displaced withrespect to each other. The actual structure can be generally braided asillustrated in Wallsten U.S. Pat. No. 4,655,771, incorporated byreference hereinto, or as found in self-expanding braided flat wireWallstent® devices. Both a cover 23 and a liner 24 are illustrated inFIGS. 1 and 2. Either cover 23 or liner 24 can be omitted if there is nodesire to substantially encapsulate the tubular support component 22.

With more particular reference to the illustrated cover 23 and liner 24,when included, they may be formed by an electrostatic spinning processin this illustrative embodiment. Details regarding electrostaticspinning techniques in general are found in Bornat U.S. Pat. No.4,323,525 and in Bornat European patent publication No. 9,941, as wellas in the Annis et al. article discussed hereinabove, the disclosures ofwhich are incorporated by reference hereinto. With further reference tothe application of this technology to the expandable supportable luminalgrafts of the present invention, random pattern filaments are formed andelectrostatically directed toward a charged mandrel in order to form arandom pattern of electrostatically generally cross-linked filamentswhich take on the configuration of a mat having a cylindrical shape. Thefilament diameters are particularly fine, as is the pore size of the matso constructed. A typical range of filament diameters is between about0.5 micron and about 5 microns, and a typical pore size of theelectrostatically spun fiber is between about 3 microns and about 20microns.

Liner 24 is formed directly on the rotating mandrel by thiselectrostatic spinning procedure. Thereafter, one of the tubular supportcomponents discussed herein, such as the generally braided tubularsupport 22, is placed over the liner 24 still on the mandrel. In thecase of the tubular support 22 in a form that is not spring loaded, thisincludes longitudinally extending the tubular support 22, such as bypulling one or both of its ends, which thereby decreases its diameter sothat it fits snugly over the liner 24. When the generally braidedtubular support 22 is of a spring-into-place type, a hold-down member(such as shown in FIGS. 18 and 20) is used to prevent automatic radialexpansion prior to deployment. When the expandable supportive graft 21is to include a cover 23, the mandrel is again rotated, and theelectrostatic spinning is again accomplished in order to form the cover23 directly over the tubular support 22. This will also create somebonding between the thus formed cover 23 and the liner 24 at openingsbetween the strands or wires of the woven tubular support 22 or thelike. This bonding can be facilitated by uniformly compressing the outerfibers with a soft silicone roller or sponge such that the still tackyouter fibers bond to the inner fibers thereby encapsulating the tubularsupport within the graft.

Bonding may also be achieved in this or other embodiments by heatwelding and/or by the use of adhesives such as hot melt adhesives,primers, coupling agents, silicone adhesives, and the like, andcombinations of these. Examples include aliphatic polycarbonate urethanehot melts and silicone rubber adhesives.

It is important to note that each of the cover 23 and the liner 24, wheneither or both are present, is made of an elastomeric material whichretains its compliant properties after construction of the expandablesupportive graft 21 is completed. In this regard, the graft itself isalso elastomeric and compliant. Accordingly, the graft 21 is deliveredtransluminally, such as by being pulled down onto the balloon of acatheter or into an inserter tube and then percutaneously inserted andpositioned to the location where the repair is needed. For a non-springloaded graft, the balloon is then inflated to longitudinally shorten andradially expand the graft 21 into engagement with the vessel walls.Because of the compliance of the cover 23 and/or liner 24, and becauseof the hoop strength of the braided tubular support 22, the graft 21will remain in place. In the illustrated embodiment, ends 25 of thetubular support are exposed and are not covered by the cover 23. Thisallows the exposed end portions 25 to directly engage the vessel wall,if desired in the particular application, in order to assist inanchoring the graft 21 in place. Liner 24 also can be sized so as to notcover the exposed ends 25, or it can extend to or beyond the edge of theends 25 when it is desired to avoid or minimize contact between thetubular support and the blood or other fluid flowing through the vesselbeing repaired or treated.

Alternatively, when a braided tubular support such as that illustratedin FIGS. 1 and 2 is incorporated into the graft according to the presentinvention in a non-spring-loaded form, transluminal delivery can be madeby way of a catheter or tool having means for longitudinally compressingthe endoprosthesis until it has expanded radially to the desiredimplanted diameter. Such equipment typically includes a member thatengages one end of the endoprosthesis and another member which engagesthe other end of the endoprosthesis. Manipulation of proximally locatedcontrols then effects relative movement of the members toward each otherin order to thereby longitudinally compress the endoprosthesis. Deliverytools for spring-loaded grafts include a sleeve that maintains the graftat its compressed diameter until the graft is positioned for deploymentsuch as from the end of an insertion catheter to its auto-expandedstate.

With reference to the embodiment illustrated in FIGS. 3 and 4, anexpandable supportive graft is illustrated at 31. The illustratedtubular support component 32 is constructed of sinusoidally configuredwire helically wound into a tubular shape. General structures of thesetypes are generally discussed in Pinchuk U.S. Pat. No. 5,019,090,incorporated by reference hereinto. A cover 33 can be positioned overthe tubular support 32 and/or a liner 34 can be positioned along itslumen. In this illustrated embodiment, the cover 33 and liner 34 areconstructed of porous polymers, the pores thereof having been made byelution or extraction of salts and the like, such as described inMacGregor U.S. Pat. No. 4,459,252, incorporated by reference hereinto.Generally speaking, the porosity is determined by the size of theelutable particles as discussed herein and by the concentration of thoseparticles as a percent by volume of a pre-elution mixture thereof withthe polymer of the cover or liner. When a graft 31 having both a cover33 and a liner 34 is prepared, a mandrel or rod is dipped into a liquidpolymer having elutable particles as discussed herein dispersedtherewithin. After dipping, the polymer covered rod is contacted with,such as by dipping or spraying, a solvent, for the elutable particles,such as water, thereby forming the eluted porous liner 34. Thereafter,the tubular support 32 is positioned thereover and pressed down into theliner. Then, the rod and the assembly thereon are again dipped into themixture of polymer and elutable particles, followed by setting andcontact with solvent to remove the elutable particles in order to formthe eluted porous cover 33. It is also possible to directly extrude theparticle-containing polymer into a tubular shape.

Elutable particles which can be used in the making of the eluted porouscover 33 and liner 34 include salts such as sodium chloride crystals,sodium carbonate, calcium fluoride, magnesium sulfate and otherwater-soluble materials that are readily dissolved by the utilization ofwater as an elution medium. Other particles that are soluble in organicsolvents and the like can be substituted as desired. Further particlesinclude sugars, proteins, and water-soluble hydrogels such as polyvinylpyrrolidone and polyvinyl alcohol. Suitable polymer materials are asdiscussed elsewhere herein, the pore size being on the order of about 10microns to about 80 microns.

As with the other embodiments, when desired, ends 35 of the supportcomponent 32 can be exposed either on one or both of its cylindricalfaces in accordance with the needs of the particular repair or treatmentto be carried out. With this approach, the exposed ends 35 will assistin maintaining the graft 32 in place by mechanical engagement betweenthe exposed ends 35 and the vessel being repaired or treated and/or bytissue ingrowth. The anchoring aspect of the exposed ends of the tubularsupport can be enhanced by continued radial expansion of the balloon orother deployment means which will permit the exposed ends to expandradially outwardly in an amount somewhat greater than that of the restof the expandable supportive graft and into the surrounding tissue. Itis also contemplated that mechanical means can be used to assist injoining the exposed ends of this embodiment or of other embodiments tothe vessel wall. An illustrative example in this regard is the use oftransluminally delivered staples which can take on the appearance ofrivets. Especially advantageous are staples made of an elastomericmaterial. Illustrated staples are shown at 36 in FIG. 3. They can beincorporated at other locations as well along the graft. One or morewindows 37 can be formed through the cover and/or liner and/or tubularsupport in order to feed outside branch arteries or other vessels.

FIGS. 5 and 6 illustrate a further embodiment of an expandable supportedgraft, generally designated as 41. Shown is a mesh tubular supportcomponent, generally designated as 42, such as those of the typeillustrated in Palmaz U.S. Pat. No. 4,733,665, incorporated by referencehereinto. These are non-woven mesh-type cylinders or slotted tubeswherein most or all of the individual components are either integrallyjoined together such as by welding or are integrally formed from asingle tube. The resulting endoprostheses are malleable enough so as tobe expandable by a balloon of a catheter. Usually, these endoprostheseshave particularly high hoop strengths.

Cover 43 and/or liner 44 are made of polymers rendered porous by phaseinversion techniques. In accordance with these techniques, a polymersuch as a polyurethane is dissolved in a solvent therefor, for example awater-soluble polar solvent, such as dimethyl acetamide, tetrahydrofuranand the like, in order to form what is known as a lacquer. A mandrel orrod is dipped into the lacquer. Thereafter, the dipped rod is contactedwith an inversion solvent, such as by dipping in water or a mixture ofalcohol and water. This inversion solvent must readily dissolve thepolymer solvent of the lacquer, while at the same time being a poorsolvent for the polymer. Under these conditions, the polymer coagulatesand the polymer solvent of the lacquer is removed and replaced with theinversion solvent. The inversion solvent pulls the polymer solvent outof the polymer on the rod and forms particularly fine pores having apore size on the order of about 0.5 micron to about 20 microns. The thusformed liner 44 having phase inversion pores is then dried.

Next, the tubular support component 42 is secured over the liner 44 andis preferably radially compressed onto and into the liner. Thereafter,the cover 43 having phase inversion pores is formed in accordance withthe same phase inversion steps as discussed hereinabove for preparationof the liner 44. If desired, either the liner or the cover can beomitted. Cover 43 and liner 44 are thus formed in accordance with adisplacing step wherein precipitating non-solvent molecules aresubstituted for non-precipitating solvent molecules dispersed throughoutthe lacquer coating. This procedure develops advantageous elasticcharacteristics. Further details regarding the phase inversion procedureare found in Lymann et al. U.S. Pat. No. 4,173,689, incorporated byreference hereinto.

FIGS. 7 and 8 illustrate an embodiment wherein the graft takes the formof a bifurcated expandable supportive graft, generally designated at 51.Included is a joined-ring bifurcated tubular support 52. Also shown area bifurcated cover 53, a bifurcated lining 54 and exposed ends 55, 56,57. This particular bifurcating graft is well-suited for insertion intoa branching vessel.

The tubular support includes a plurality of rings or loops 58 connectedby flexible interconnections 59. Constructional details of embodimentsof the rings or loops 58 and of the flexible interconnections 59 arefound in MacGregor U.S. Pat. No. 4,994,071, incorporated by referencehereinto. The flexible interconnections 59 join the rings or loops 58into a configuration having a main body or trunk 61 and one or morebranches 62. Flexible interconnections 59 extend longitudinally from theaxis of each of the main body or trunk 61 and branch 62, 63. At leastone such flexible interconnection joins each branch to the trunk. Theloops 58 in the main body are substantially parallel to each other, andthe loops 58 in each branch 62, 63 are substantially parallel to eachother.

The bifurcated cover 53 and bifurcated liner 54 must each, whenprovided, be especially elastomeric so as to follow the expansion andcontraction of the rings or loops 58 that takes place duringpreparation, transluminal insertion, deployment and the like. Cover 53and liner 54 will also take on a bifurcated construction. In oneembodiment, the liner and/or cover for each of the trunk 61 and branch62, 63 are made on a cylindrical mandrel, assembled and joined, such asby suitable biocompatible adhesive, fusion, sewing, suturing or othermeans of joining and/or sealing. Alternatively, a Y-shaped or branchedmandrel can be used. The bifurcating liner is then formed thereon byprocesses such as those discussed herein, including electrostaticspinning, or dipping followed by elution or phase inversion proceduresmuch in the same manner as described herein when straight cylindricalmandrels or rods are used for constructing the non-bifurcated grafts inaccordance with this invention. Fiber winding can also be practiced.Bifurcated cover 53 is made in a similar manner by application of theporous cover material over the bifurcated endoprosthesis.

With reference to the bifurcated endoprosthesis, the bifurcated cover 53and/or bifurcated liner 54 could be made by fiber winding approaches,such as those described in Wong U.S. Pat. No. 4,475,972, the subjectmatter thereof being incorporated by reference hereinto. Polymer insolution is extruded into fibers from a spinnerette onto a rotatingmandrel. The spinnerette is reciprocated along the longitudinal axis ofthe mandrel at a controlled pitch angle, resulting in a non-wovencylinder wherein each fiber layer is bound to the underlying layer.Control of the pitch angle allows for control of the compliance and kinkresistance of the cover and/or liner. In an especially advantageousarrangement when using these fiber spinning techniques in forming anexpandable supportive graft in accordance with the general aspects ofthis invention which has both a liner and a cover, the cover isphysically bonded to the liner by the use of an electrostatic field toenable penetration of the cover overlay of fibers through theinterstices of the support components in order to improve the bonding ofthe cover and/or liner fibers to each other and/or to surfaces of thesupport component.

With more particular reference to balloon deployment of expandablesupportive grafts, this is illustrated with some particularity inconnection with bifurcated endoluminal grafts in FIGS. 9, 10, 11, 12 and13. As shown in FIG. 9, two guidewires 64, 65 are inserted into thebifurcating vessel, each of them into different legs 66, 67 of thebifurcating vessel. Thereafter, the unexpanded bifurcated expandablesupportive graft 51 is slipped over the proximal ends of the guidewiresand routed to the branches of the blood vessel. The unexpandedbifurcated graft can be introduced from an arteriotomy proximal to thebifurcation such as from the brachial artery in the arm, or theunexpanded bifurcated graft can be introduced from the femoral artery inthe leg, pushed proximally past the bifurcation and then pulled backdistally into both iliacs to form the trunk and bifurcation.

The two branches 62, 63 of the graft 51 are routed separately over theguidewires 64, 65, respectively, and guided, typically with the help ofa guide catheter, into the patient until the graft is positioned asshown in FIG. 9. The graft 51 is initially fixed in place as follows.One of the guidewires 65 is removed, and a balloon catheter 68 isinserted into the main body or trunk 61 and inflated to expand the trunk61 into contact with the vessel walls. This deployment is suitable tosecure the graft 51 in place at that location of the vessel.

The balloon of balloon catheter 68 is then deflated. If this ballooncatheter is also suitable for use in expanding the branches 62, 63 ofthe graft 51, same is then inserted into an unexpanded branch 62 andradially expanded as generally shown in FIG. 11. If the balloon ofcatheter 68 is not suitable in this regard, then another ballooncatheter 69 effects this function. FIG. 12 shows inflation of the otherbranch 63 of the graft 51 in a similar manner. FIG. 13 illustrates thefully deployed and expanded bifurcated support graft 51 positioned inplace within the bifurcated location. Alternatively, a bifurcateddilation balloon on a bifurcated catheter (not shown) can replace thesingle-balloon catheter(s) 68, 69.

Preferably the branched and assembled expandable supportive graft is ofthe spring-into-place type; as such, it will be manipulated to bereduced in diameter and placed within an overlying and bifurcatedrestraining guiding catheter or the like and will be passed overguidewires and contained within the guiding catheter until properplacement within the bifurcating location. This type of bifurcatedexpandable supportive graft is deployed by being ejected into place,typically by advancing a small inner catheter through the guidingcatheter into contact with the bifurcating graft in accordance with theprocedure generally used for spring-into-place stents.

The deployment procedures illustrated in FIGS. 9 through 13 can becharacterized as prograde deployment. Retrograde deployment is alsopossible. The entire bifurcating graft for retrograde deployment isadvanced over a single guidewire through one branch of the blood vesselpast the point of bifurcation. A second guidewire is then steered downthe opposite limb of the graft, and a snare is used. The snare, which ispassed retrograde through the opposite vessel, is then used to pull theguidewire into place. Partial balloon inflation in the unbranched ortrunk portion of the blood vessel is then used to draw the graft downinto position prior to balloon dilatation of both the trunk and branchedportions of the graft. Because blood flow is prograde under thesecircumstances, the contact between the bifurcation of the graft and thebifurcation of the blood vessel helps to prevent the graft frommigrating distally, thus reducing the need for active fixation of thegraft to the blood vessel.

Another bifurcated endoprosthesis or expandable supportive graft isgenerally designated 81 in FIG. 14. Separate components are included. Inthis case tubular supporting component(s) are, prior to deployment,separate from a trunk component. In this embodiment, a fully independenttubular supporting component 82 is located at the trunk position of thegraft 81. A bifurcated stretchable wall 83 is in contact with theindependent tubular supporting component 82 as either or both of a coveror liner. In addition to being substantially coextensive with theindependent tubular supporting component 82 at a trunk portion 84thereof, the stretchable wall 83 includes at least two generally tubularstretchable branch sleeves 85, 86 which are initially devoid of asupporting component. Separate tubular supporting components 87, 88(FIGS. 16 and 17) are also included.

Implantation of this bifurcated expandable supportive graft is depictedin FIGS. 14, 15, 16 and 17. Dual guidewires 64, 65 can be used toproperly position the unexpanded bifurcated graft 81 within thebifurcating vessel as shown in FIG. 14. A balloon catheter 68 orsimilarly functioning device is inserted into the main body of thedevice so as to expand the independent tubular supporting component 82and the trunk portion 84 of the bifurcated stretchable wall 83. Thisdeployment initially secures the bifurcated supporting graft into placeat that location of the vessel, as shown in FIG. 15. The ballooncatheter is then deflated and removed or positioned for use in the nextstep.

A suitable balloon catheter 69 or the like is next used to deploy andexpand in place a branch tubular expandable supporting component 89, asillustrated in FIG. 16. A similar step deploys and expands in placeanother branch tubular expandable supporting component 90, as generallyshown in FIG. 17. The bifurcated stretchable wall 83 and the expandablesupporting components may be made with the materials and constructionsdiscussed herein and may be subjected to various treatments asdiscussed.

A further bifurcated endoprosthesis or expandable supportive graft isone in which the separate components are each expandable supportivegraft members. These separate components are illustrated in FIG. 18through FIG. 21, which also illustrate their separate deployment withrespect to each other within an aortic trunk. Same is shown inconnection with treating an aneurysm such as an abdominal aorto-iliacaneurysm. The device includes a trunk component 101 which, in theillustrated use, is designed to extend from below the renal arteries toa location between the proximal neck of the aneurysm and the aorto-iliacbifurcation. It will be understood that this trunk component could alsobe shorter so that it terminates just below the proximal neck of theaneurysm, for example of a length which terminates within the dent orcrease 124. In addition, the component bifurcated expandable supportivegraft of this embodiment is self-expanding and is deployed by means ofan introducer containing compressed expandable supportive graftcomponents.

More particularly, and with reference firstly to FIG. 18, a guidewire102 is first inserted in accordance with known procedures so as totraverse the aneurysm 103. Next, an introducer, generally designed as104 having the trunk component therewithin in a radially compressedstate is inserted over the guidewire 102. The introducer is maneuveredsuch that it is properly positioned as desired, in this case at alocation distal of the distal end of the aneurysm. Then, the sheath 105of the introducer is withdrawn, such as by sliding it in a proximaldirection while the remainder of the introducer 104 remains in place. Asthe sheath is withdrawn, the trunk 101 expands, eventually achieving thedeployed or implanted position shown in FIG. 19. At this stage, thedistal portion 106 of the trunk is well anchored into the blood vesselwall and is suitably deployed.

FIG. 20 shows an introducer, generally designated as 107, having anindependent tubular expandable supportive graft leg component 108 (FIG.21) radially compressed therewithin. In this illustrated embodiment,this leg component is an iliac component of the bifurcated supportivegraft being assembled within the body vessel. The introducer 107 isadvanced until this iliac component is moved into a leg 109 of thealready deployed trunk component 101. This positioning is illustrated inFIG. 21. It will be noted that the iliac tubular supportive graftcomponent 108 extends from well within the leg 109 to a locationproximal of the aneurysm in the iliac artery 110.

In a previous step, a guidewire had been passed through the appropriatevessel to iliac artery 112 until it crossed the aneurysm 103, whilepassing through the other leg 113 of the deployed trunk component 101.When the introducer for the previously radially compressed iliaccomponent 115 had been removed, the component 115 had expanded radiallyand was deployed. Thus, the entirety of the bifurcated endoprosthesis orexpandable supportive graft in accordance with this embodiment is fullydeployed and assembled together as shown in FIG. 21, as well asgenerally depicted in FIGS. 29 and 30.

It will be noted that it is not required to actually attach the trunkcomponent 101 and the tubular components 108, 115 together. In otherwords, these components are generally telescopically positioned withrespect to each other. This telescopic feature allows some slippagebetween the trunk component and the tubular leg components, therebyproviding a telescopic joint which functions as a slip bearing. It willbe appreciated that it is generally desirable to firmly anchor portionsof the bifurcated endoprosthesis within healthy vessel wall tissue. Thiscan be achieved by the hoop strength of the supportive graft or bytaking measures to enhance hoop strength at its ends, or by providinggrasping structures such as hooks, barbs, flared ends and the like.During pulsetile blood flow and possibly during exercise by the personwithin which the endoprosthesis is implanted, tension and elongationforces are imparted to the endoprosthesis. In structures that do nothave a telescopic joint or some other means to relieve the stressdeveloped by this tension, a considerable amount of stress can be placedon the anchoring sites and/or the attachment components, potentiallyallowing for dislodgement at the anchoring sites or breakage ofattachment components.

FIGS. 22, 23, 24 and 25 further illustrate a trunk component 101. Itincludes a common trunk portion 118 and a branched portion, generallydesignated as 119. The branched portion includes the legs 109 and 113.In this embodiment, a further common trunk portion 120 is locatedopposite the other common trunk portion 118 and extending from thebranched portion 119. Thus, the overall configuration of the trunkcomponent is that of a double-lumen length located between twosingle-lumen lengths. The common trunk portion 118 can be positioned,for example, in the aortic artery, the branched portion 119 provides abifurcation structure to direct blood flow into the two iliac arteries,and the further common trunk portion 120 facilitates deployment of theleg components into the branched portion 119, acting in the nature of afunnel for each guidewire, introducer and contracted leg component.

Trunk component 101 includes a stent or tubular supporting component121. Also included is a liner, generally designated as 122. A furtherliner 123 preferably is located interiorly of the liner 122. Liners 122,123 are secured within the stent component 121 in order to provideproper porosity for an endoprosthesis.

Trunk component 101 includes one or more indents, such as indent 124 andindent 125. A third, a fourth, or further indents can be provideddepending upon the degree of branching desired. It will be appreciatedthat one or more tubular expandable supportive leg graft components willbe provided in order to slide into the branched passageways which arethus defined by the indent(s). In the illustrated embodiment, one suchleg component 108 slidingly engages an opening 126 of the trunkcomponent leg 109, while a second leg component 115 slidingly andexpansively fits within opening 127 of the leg component 115.

With particular reference to FIGS. 31-33, this shows a trunk component101 c which has a function and a configuration along the lines of trunkcomponent 101, except only the liner defines the indent or indents. Inthis arrangement, the tubular supporting component is cylindrical incross-section substantially throughout its length.

FIG. 31 illustrates the trunk component 101 c. It includes a commontrunk portion 118 c and a branched portion, generally designated as 119c. The bifurcated or branched portion includes the legs 109 c and 113 c.In this embodiment, a further common trunk portion 120 c is locatedopposite the other common trunk portion 118 c and extends from thebranched or bifurcated portion 119 c. Thus, as with trunk component 101,the overall configuration of trunk component 101 c is that of adouble-lumen length located between two single-lumen lengths.

Trunk component 101 c includes a stent or tubular supporting component121 c, as perhaps best seen in FIG. 32. Also included is a liner,generally designated as 122 c. This liner 122 c has a body portion 123 cand the legs 109 c and 113 c which open into another body portion 151.

Each leg 109 c, 113 c is secured to the generally tubular stentcomponent 121 c at outside portions thereof, particularly at adhesionzones 124 c and 125 c. The remainder of the leg portions 109 c and 113 care not so bonded to the stent portion 121 c. This facilitates formationof the leg portions, which are typically pinched along the length of thelegs in order to form at least one internal seam 126 c. Leg openings 127c and 128 c are thereby generally defined between this seam 126 c andthe adhesion zones 124 c and 125 c.

In FIG. 33, means are included in the trunk component 101 d whichprovides enhanced securement upon implantation. A stent component 129 dis included which has a substantially higher pitch angle (for example,between about 140° and 180°) than does the stent portion 121 dtherebelow within which the legs are positioned (for example, at a pitchangle of between about 70° and 90°). This higher pitch angle zoneimparts a greater hoop strength upon deployment than does the stent 121c of the trunk component 101 c. A barb 130 is also shown in order tofurther assist in securement of the endoprosthesis to the artery wall.When desired, the barb-type of structure can be a backing ring and barbformed out of the stent strand during its formation into the cylindricalsupportive member.

Any of the various expandable supportive endoluminal graft, or stentgraft, constructions discussed or referred to herein can be used inorder to construct devices in accordance with this embodiment. Othermodifications may also be incorporated, including tubes having steppeddiameters or conical ends. The stent component can be made with flatwires or with pairs of wires or multifilament wires. They canincorporate balloon expandable stents, self-expanding stents, andcombinations of balloon expandable stents and self-expanding stents. Usecan be made of ancillary equipment such as endoluminal stapling devicesor suturing devices in order to facilitate securement at the aneurysmneck, for example. Also, a portion of the stent component without aliner component or the like thereon can project at the proximal end ofthe endoluminal component, such as at a location which would be abovethe renal arteries. The objective is also to help to secure the devicein place.

The prosthesis as discussed is deployed to replace or repair tubularbodies such as blood vessels, tracheas, ureters and the like,accommodating more than one conduit in order to divert flow to otherbranches of the tubular body. This allows for repair of a bifurcatedarea which is difficult to repair using a single-lumen device or aplurality of individual single-lumen devices. It is suitable for repairof damages to branched conduits or, conversely, to repair conduits whichconverge into a single branch.

A preferred use for the bifurcating endoluminal grafts discussed hereinis for insertion into a branching blood vessel. Same is typicallysuitable for use in the coronary vasculature (the right, left common,left anterior descending, and circumflex coronary arteries and theirbranches) and the peripheral vasculature (branches of the carotid,aorta, femoral, popliteal arteries and the like). These bifurcateddevices are also suitable for implantation into other branching vesselssuch as in the gastrointestinal system, the tracheobronchial tree, thebiliary system, and the genitourinary system.

It will be appreciated that the expandable supportive grafts inaccordance with the present invention will dilate and/or support bloodvessel lesions and other defects or diseased areas, including at or inproximity to sites of vascular bifurcations, branches and/oranastomoses. The expandable supportive graft is an integral structurethat incorporates the expandable support component into the wall orwalls of the elastomeric graft. Covers and/or linings that make up thegrafts interface with body components that facilitate normal cellularinvasion without stenosis or recurrent stenosis when the graft is in itsexpanded, supportive orientation. The graft material is inert andbiocompatible. The expandable supportive graft can be expanded from asmaller diameter insertion configuration to a larger diameterimplantation configuration by the application of radially outwardlydirected forces provided by expanding the endoprosthesis with a ballooncatheter, using an ejection tube that allows a spring-into-placestructure to be deployed from the end of a catheter into its expandedconfiguration, or by using a support component made of certain alloysexhibiting thermotransition characteristics by which they expand whenheated, for example.

In addition to the support component structures illustrated herein,support structures include others having spring characteristics andthose having a coil with circumferentially oriented fingers such asshown in Gianturco U.S. Pat. No. 4,800,882, incorporated by referencehereinto. U.S. Pat. Nos. 5,061,275, 5,219,355 and 5,336,500 relate toexpanding or self-expanding endoluminal devices. Typically, thesedevices center on the use of a metallic structure imparting expansionattributes. U.S. Pat. Nos. 4,994,071 and 5,360,443 describe bifurcateddevices which use expandable metallic stent structures and textilematerials allowing branching of fluid flow. In general, materials ofthese patents, incorporated by reference hereinto, can be utilized inconstructing components of the present invention.

More specifically, the tubular supportive component preferably is abraided tubular stent body made of metal alloy or any other materialthat is flexible, while being rigid and resilient when thus braided.Spring-type metals are typically preferred, such as stainless steel,titanium, stainless steel alloys, cobalt-chromium alloys, includingalloys such as Elgiloy, Phynox and Conichrome. Thermal transition ormemory function alloys such as nickel-titanium alloys including Nitinolare also suitable. Malleable metals including tantalum would beespecially suitable for a structure that is not self-expanding.

Concerning the materials for the liner(s), they are typically polymericmaterials in the form of a membrane or textile-like material, theobjective being to reduce the porosity of the stent for proper tissueingrowth and fluid tightness. Exemplary polymeric materials includepolyesters such as polyethylene terephthalate, polyolefins such aspolypropylene, or elastomeric materials such as polyurethane or siliconerubber. Combinations of these materials are also possible. In anespecially preferred arrangement, the exterior liner which engages thetubular supportive component 121, when provided, is made of a doubletricot polyester mesh knit, typically a Dacron type of material, whilethe interior liner 122 c is made of a polyurethane. In an especiallypreferred arrangement, a thin coating or cover of polymer is providedover the braided wires of the tubular supportive component.

With further reference to the material out of which the cover and/orliner of the grafts in accordance with the present invention are made,the material must be stretchable with respect to the support componentso that it will follow the movement of the endoprosthesis between itsfully collapsed and expanded or implanted configurations. Polyurethanesare preferred. Particularly preferred is an especially crack-resistant,elastomeric and pliable polycarbonate urethane as described in PinchukU.S. Pat. Nos. 5,133,742 and 5,229,431, incorporated by referencehereinto.

In addition, various surface treatments can be applied to render thesurfaces of the expandable supported graft more biocompatible. Includedare the use of pyrolytic carbon, hydrogels and the like. The surfacetreatments can also provide for the elution or immobilization of drugssuch as heparin, antiplatelet agents, antiplatelet-derived growthfactors, antibiotics, steroids, and the like. Additionally, the coatingand/or liner can be loaded with drugs such as those discussed herein, aswell as lytic agents in order to provide local drug therapy.

It will be noted that the indent(s) such as indents 124, 125 and theseams(s) such as internal seam 126 c are longitudinally disposed andgenerally define at least two leg portions, each with a diameter lessthan the diameter of the main body. Each indent has an internallongitudinal surface such as longitudinal edge 128, 129. These edges canbe in contact with one another. If desired, they can be secured togethersuch as with sutures, adhesives, wires, clips or the like (not shown).One or two such indents or creases produce an asymmetrical or asymmetrical bifurcation as desired. In another exemplary approach, threeindents would form a trifurcated device. Additional creases can beprovided insofar as is allowable by the braided wire mesh density anddiameter.

Seam 126 c can be formed by joining together two or more longitudinalportions of the liner 122 c. When two such longitudinal portions arejoined together, they are generally opposite to each other. When threesuch longitudinal portions are joined together, they are approximately120° from each other along the circumference of the liner 122 c, andthree legs are formed. When four such longitudinal portions are joinedtogether, for example, they are spaced approximately 90° apart.

Whatever the number of indents or seams, the deformation of the braidedtubular body reduces the cross-sectional area from that of the maintrunk body to that of each branched area. The total cross-sectional areaof the branching tubular bodies should be equal to or greater than 40%of the cross-sectional area of the main trunk body. Preferably, thisarea should be greater than about 70% in order to prevent anysignificant pressure differences along the device once deployed andimplanted. For example, in a typical human, the cross-sectional area ofthe abdominal aorta is reduced by only about 20% when opening into thecommon iliac arteries.

FIG. 26 illustrates a fixture suitable for use in forming the indent orindents as permanent deformations of the braided mesh cylinder which isthe tubular supportive component for this embodiment. Fixture 131 in theconfiguration as illustrated is used for shaping a symmetricalbifurcated design. The braided cylinder is longitudinally compressed andplaced over the mandrel 132, this placement being generally shown inFIG. 27. End caps 133, 134 lock the tubular supportive component 121 inits compressed state. Same is then placed into the fixture 131, asgenerally shown in FIG. 26. Slits 135 are positioned parallel to thelongitudinal axis and on opposite sides. This permits the slipping ofblades 136, 137 into the fixture 131 and thus into engagement with thetubular supportive component. Edges 138, 139 of the blades then engageand crease the tubular supportive component 121 between the blade edges138, 139 and the troughs 141, 142 of the mandrel 132.

It will be appreciated that the length of the blade edges 138, 139 canbe varied in order to create a desired length of deformation on the mainbody of the trunk component. In addition, branching areas thus formedcan be made of different sizes by varying the size of the individualcylindrical components of the mandrel 132 so they are not identical asshown in FIG. 26. A larger sized mandrel cylinder will result in theformation of a larger trunk component leg 109, 113. This would typicallyalso include shifting the location of the slits 135 so that the plane ofblade insertion will line up with the troughs. It will be appreciatedthat the trifurcated arrangement is achieved by a three-componentmandrel and three slits and blades that are 120° apart. Similarly, afour-branched structure would include four of each features, spaced 90°apart.

In a preferred arrangement for this embodiment, the thus deformedbraided tubular supportive component is chemically and heat processed inorder to set the desired diameter and mechanical properties of the mainbody. Once this flexible metallic stent with conformed shape is thusprepared, it is preferably lined as discussed elsewhere herein. It willbe noted that the illustrated tubular braided mesh has a maincross-sectional area and has an outward flair at both ends. The braidedstructure is advantageously accommodated by the serrated structure ofthe blade edges 138, 139 in that the wire elements of the braid aregrasped and secured at the ends of the bifurcation.

The expandable supportive graft of the present invention is capable ofbeing tailored to meet specific needs, depending upon the particulardefect or disease being addressed, such as occlusion, stenosis,aneurysm, arteriovenosis fistula, trauma and the like, as well as uponthe anatomy of the vessel. For example, it can be desirable to have thesupport component of the expandable supportive graft at locations otherthan throughout the entirety of the graft as specifically illustrated inFIGS. 1 through 4 hereof. The bifurcated graft of FIGS. 7 and 8 showssome separation along the support component, such as between the trunk61 and the branches 62, 63. It is also possible, with the grafts inaccordance with the present invention, to provide an expandable grafthaving its supportive property emanating from one or more supportcomponents, while thereby providing an adjoining graft cylindricalportion which is supported primarily by its close proximity to a supportcomponent which can be presented at one end, both ends, or spaced alongthe expandable supportive graft in accordance with the invention.

Such a structure is generally illustrated in FIG. 5, wherein anadjoining graft cylindrical portion 71 is positioned between a firstsupport component 72 and another or second support component 73. Theexpandable supportive graft in accordance with the present inventionprovides the tailorability advantage of being able to vary within asingle graft the configuration, structure and properties of the supportcomponent or components of the graft. These various properties allow theexpandable supportive graft to be tailored in accordance with particularneeds of the disease, defect or damage being treated. For example,support may be particularly desirable at one location being treated,while a less rigid supportive area is needed at another, generallyadjoining location. By the expandable supportive graft in accordancewith this invention, a single graft can be deployed in order to effecttwo or more different functions. By achieving multiple support and/orrepair functions with a single device, possible trauma to the patient isminimized by reducing the number of transluminal passages needed toaddress a situation that could otherwise require separate stents orgrafts, each of which is separately deployed or implanted.

With further reference to the tailorability aspects, the presentinvention reduces the risk of compromising the patency of thepassageways being treated. This is particularly true in treating lesionsat or near vascular bifurcations, branches and/or anastomoses. Typicaldifficulties which can be avoided by the present invention includedisplacing of diseased tissue, vessel spasm, dissection with or withoutintimal flaps, thrombosis, embolism, and the like. Another suitable useis for dilating and/or supporting vascular graft bifurcations and thelike. Additionally, lesions affecting vascular trifurcations can betreated. Also treatable are obstructed openings characterized byexaggerated cicatrization, abnormal cellular growth (subintimalfibromuscular hyperplasia and the like) or arterial or venous stenosis.Moreover, these supportive grafts can be used to reinforce vascularwalls, weakened by pathological processes, for example, by dissection,as in the case of aneurysms. The grafts can also obliterate congenitalor acquired arteriovenous communications, and they can be applied inintrahepatic portal-caval shunts. The grafts also can maintainbiological pathways open, such as the digestive, biliary, pancreatic andurinary tracts, and they help to limit the intraluminal growth ofpathological processes such as fibrosis or cancer.

EXAMPLE I

This example illustrates the formation of a branched expandablesupportive endoluminal graft having an expanded internal diameter of 10mm and which is bifurcated to accommodate two endoluminal supportivegraft legs of 5 to 7 mm in diameter. A liner of non-woven polycarbonateurethane (Corethane®) was spun by winding over a mandrel, generally inaccordance with U.S. Pat. No. 4,475,972. In this instance, the linerconsisted of approximately 400 layers of fibers. A bifurcated braidedmesh tubular supportive component made in a fixture as illustrated inFIG. 26 was spray coated using a dilute solution of polycarbonateurethane having a hardness grade and a melting point lower than thatused to spin the liner. It was allowed to dry with warm air. Severalspray coats allow for the formation of an adhesive layer.

The previously prepared polycarbonate urethane liner was cut to lengthand placed inside the adhesive-coated bifurcated braided mesh and seatedto closely fit the bifurcated braided mesh. A mandrel having a shapesimilar to the inner configuration of the bifurcated mesh was insertedfrom one end to act as a support. Shrink tubing was slipped overportions of this assembly. This assembly was heated to the melting pointof the polycarbonate urethane adhesive while allowing the shrink tubingto heat shrink and compress the braided mesh against the liner which issupported by the shaped mandrel. After cooling, the shrink tubing wasremoved and the mandrel slipped out, leaving a completed trunk componentas described herein.

The two endoluminal tubular expandable supportive graft leg componentsare prepared in accordance with a similar procedure which is simplerbecause of the cylindrical shape of these components.

EXAMPLE II

The procedure of Example I is substantially repeated, except the lineris a double tricot polyester mesh net. In a similar arrangement, a trunkcomponent of the same structure was formed, except prior to insertion ofthe supporting mandrel, a second, innermost liner of polycarbonateurethane is positioned in order to provide a double-lined branchedcomponent.

EXAMPLE III

The procedures of Example I and of Example II are generally followed,except here the expanded inner diameter of the trunk component is 25 mm,and the cylindrical leg endoluminal grafts are 12-15 mm in diameter.

EXAMPLE IV

A branched vascular expandable supportive endoluminal graft was madeusing a 16 mm diameter, 12 cm long Wallstent® device as the supportcomponent in the following manner. A grounded 16 mm mandrel was rotatedon a spinning machine at 500 RPM, and a spinnerette with 30 orifices wasreciprocated along the axis of the mandrel at 13.8 inches/second whileapplying 40,000 volts to the spinnerette. Polycarbonate urethane, indimethyl acetamide solution (45% solids) was extruded from thespinnerette at 0.123 ml/min, the fibers coming onto the mandrel inrandom fashion to form a mat-like structure having randomly shapedpores. The environment in the spinning chamber was controlled such thatsufficient solvent from the urethane solution evaporated off duringspinning to enable the fibers to be bond to underlying fibers duringeach transverse of the spinnerette. After 300 passes of the spinnerette,the spinning procedure was stopped and the mandrel with the spunpolycarbonate urethane mat was removed from the machine and cured at110° C. for 16 hours. The tubular mat still on the mandrel was trimmedto the appropriate size and the Wallstent® device was sheathed over themesh and the ends taped down. Another 10 passes of polycarbonateurethane were spun over the Wallstent® device, and the fibers, whilestill wet, are immediately pressed through the interstices of theWallstent® device with a silicone rubber sponge at selected longitudinallocations, such that the fibers bond to the underlying fibers of theurethane mat, thereby capturing the Wallstent® device within theurethane wall along those longitudinal locations. The assembly is thencured for an additional 3 hours at 110° C., after which the assembly isremoved from the mandrel. The expandable supportive endoluminal graftformed in this manner had the bulk of the urethane mesh on the inside ofthe stent. The longitudinal locations which are not secured to the stentare joined together to form a seam to define two legs as generally shownin FIG. 31.

EXAMPLE V

A branched aortic expandable supportive endoluminal graft is made in thefollowing manner. An aortic trunk supportive endoluminal graft isfabricated using a 16 mm diameter, 12 cm long support component. First,a 16 mm mandrel is rotated on a spinning machine at 500 rpm, and aspinnerette with 30 orifices reciprocated along the axis of the mandrelat 13.8 inches/second. Polycarbonate urethane, in dimethyl acetamidesolution (45% solids) is extruded from the spinnerette at 0.123 ml/minand wound onto the rotating mandrel such that the fibers form a 50°pitch angle in relation to the axis of the mandrel. The environment inthe spinning chamber is controlled such that sufficient solvent from theurethane solution evaporates off during spinning to enable the fibers tobond to underlying fibers during each transverse of the spinnerette. Theformed spun polycarbonate urethane mesh has a length of about 16 cm, isremoved from the machine and is cured at 110° C. for 16 hours. Thesupport component is sheathed over the mesh still on the mandrel.Another 10 passes of polycarbonate urethane are spun over the tubularmesh, support component, but not over the 4 cm excess length of theinternal tubular mesh, and the fibers, while still wet, are immediatelypressed through the interstices of the support component with a siliconerubber sponge, such that the fibers bonded to the underlying fibers ofthe urethane mesh, thereby capturing the support component within theurethane wall. The assembly is then cured for an additional 3 hours at110° C., after which the assembly is removed from the mandrel. Thesupportive endoluminal graft formed in this manner has fiber diametersof 10 to 20μ and pore sizes ranging from 10 to 60μ. The length of thetubular mesh which is spaced about 4 cm from each side of the assembledendoprosthesis is then slit and sewn down the center such that the tubeis branched into two smaller tubes along about 8 cm of the longitudinalcentral length of the tubular mesh.

The aortic trunk endoprosthesis is pulled down and sheathed on anintroducer catheter, maneuvered into the aorta of a dog, via the dog'sfemoral artery for deployment in the abdominal aorta. Two smallerstents, of 8 mm diameter, are also pulled down onto introducer cathetersand maneuvered, through each femoral artery for deployment into theseam-defined two smaller tubes or “legs” of the aortic trunk. Theresultant branched endoprosthesis is for limiting further dilation of anabdominal-iliac aneurysm.

EXAMPLE VI

A branched expandable supportive endoluminal graft is provided fordeployment within and repair of aorto-iliac aneurysms. A generallytubular metallic stent of the self-expandable type is adhered to theoutside of a porous spun liner as follows. The graft is wound or spunfrom filaments deposited onto a rotating mandrel in order to form acylindrical graft having crossing strands generally adhered together.The resulting inner liner, after it is dried, has a stent componentplaced over it. Then, an area of the stent is masked, such as with apiece of tape, at the location where an internal seam is to bepositioned in the trunk component of the supportive endoluminal graft.The masking can take on a shape on the order of the triangular areasillustrated in FIG. 32, with the upper apex forming the upper “crotch”of the seam, and the lower apex forming the lower “crotch” of the seam.Additional fibers are then spun over the entire stent and pressedthrough the stent intersticies to be certain that the stent is securedto the liner. This continues until all areas of the stent arewell-bonded except for the masked areas. After removal of the mandreland of the masking material, the initially formed inner liner is free tobe pinched along its length and sutured, sewed and/or glued and the liketo form two distinct leg portions and a trunk portion of the liner. Theresulting trunk component is as generally shown in FIGS. 31 and 32.

The leg components of the branched supportive endoluminal graft inaccordance with this Example are individually made in a similar manner.The liner is formed by spinning compliant fibers over a rotatingmandrel, a tubular stent component is positioned thereover and securedin place, and additional fibers are wound with the rotating mandrel. Thestent is thus encapsulated between the liner fibers and the coverfibers, preferably with the aid of a soft roller or sponge to force thecover strands into the interstices of the stent component and securementto the underlying liner fibers. After removal from the mandrel, theresulting tubular supported graft component, suitable for use as boththe iliac components, is trimmed to proper length.

EXAMPLE VII

A branched aortic expandable supportive endoluminal graft was made usinga liner of polycarbonate urethane. The cylindrical liner was flattened,and a longitudinal seam was formed by heat sealing together theflattened opposing portions along a thus formed seal line. Aself-expanding cylindrical stent-like support component was coated on atleast its inside surface with a heat-activated adhesive. The seamedliner was inserted into the stent-like support component, and the linerwas inflated until the two non-seamed portions of the liner and theradially extending portions of the seamed portion of the liner engagedthe inner surface of the support component. Then, this assembly with theinflated liner was placed into an oven to activate the adhesive whereby,upon subsequent cooling, the seamed liner was secured to the supportcomponent to form a branched trunk component as shown in FIGS. 31 and32. In this example, the inflation of the liner was carried out bypacking the seamed liner with salt crystals so the liner stretches inplace and until adhesion between the liner and the support component hadoccurred.

EXAMPLE VIII

A branched trunk component is prepared as described in Example VII,except the liner inflation is carried out by expanding balloon activity,and the seam is formed by suturing. Because the branched trunk componentwill elongate when collapsed for entry into the delivery tool, thesuturing allows for longitudinal expansion and contraction back down tothe as-manufactured seam length. Such suturing is achieved by using azig-zag stitch pattern.

EXAMPLE IX

Another branched trunk component is made as described in Example VIII,except the liner inflation is carried out by a mandrel, and the suturedseam is formed with a polyurethane compliant suture material.

It will be understood that the embodiments of the present inventionwhich have been described are illustrative of some of the applicationsof the principles of the present invention. Various modifications may bemade by those skilled in the art without departing from the true spiritand scope of the invention.

1-42. (canceled)
 43. An endoluminal support device comprising: aradially-expandable, bifurcated support, the support including: a firstsupport portion, and a second support portion including a first lobe anda second lobe, and a longitudinal isthmus between the first lobe and thesecond lobe, the first and second lobes having smaller diameters thanthe first portion; and a liner coupled to the radially-expandable,bifurcated support, wherein the endoluminal support device has anuninterrupted cross-section over its entire length.
 44. The endoluminalsupport device of claim 43, wherein the liner is coupled to an interiorside of the radially-expandable, bifurcated support.
 45. The endoluminalsupport device of claim 43, wherein the liner is coupled to an exteriorside of the radially-expandable, bifurcated support.
 46. The endoluminalsupport device of claim 43, wherein each of the first and second lobesis adapted to receive a branch support.
 47. A branching endovascularprosthesis comprising: a radially expandable support, the supportincluding: a distal support portion comprising at least one expandablecircumferential portion, and a proximal support portion including afirst lobe and a second lobe separated from the first lobe by anisthmus, and a bifurcated liner coupled to the distal support portionand to the proximal support portion, wherein the branching endovascularprosthesis has an uninterrupted cross-section over its entire length.48. The prosthesis of claim 47, wherein the bifurcated liner is coupledto an interior side of the distal support portion and to an interiorside of the proximal support portion.
 49. The prosthesis of claim 47,wherein the bifurcated liner is coupled to an exterior side of thedistal support portion and to an exterior side of the proximal supportportion.
 50. The prosthesis of claim 47, wherein the prosthesis is selfexpanding.
 51. A branching endovascular prosthesis comprising: a distalsupport portion comprising at least one radially expandable portion; aproximal support portion coupled to the distal support portion, theproximal support portion including a first radially expandable lobe anda second radially expandable lobe separated from the first lobe by anisthmus; and a bifurcated liner coupled to the distal support portionand to the proximal support portion, wherein the branching endovascularprosthesis has an uninterrupted cross-section over its entire length.52. The prosthesis of claim 51, wherein the bifurcated liner is coupledto an interior side of the distal support portion and to an interiorside of the proximal support portion.
 53. The prosthesis of claim 51,wherein the bifurcated liner is coupled an exterior side of the distalsupport portion and to an exterior side of the proximal support portion.54. A branching endoluminal prosthesis comprising: a liner and aradially expandable support coupled to said liner; wherein said linercomprises: a main body having a proximal portion and a distal portion,said proximal portion including a main lumen, and said distal portionincluding a first branch having a first lumen extending to a firstdistal end, and a second branch having a second lumen extending to asecond distal end, the first and second branch lumens being incommunication with the main lumen and extending through said distalportion to define a bifurcation extending to said first and seconddistal ends; and wherein said support comprises: a distal supportportion disposed over said distal portion of said main body, said distalsupport portion comprising at least one expandable circumferentialportion defining a first lobe supporting said first branch, a secondlobe supporting said second branch, and opposed indentations to supportand separate said first and second branches, wherein said branchingendoluminal prosthesis has an uninterrupted cross-section over itsentire length.
 55. The branching endoluminal prosthesis of claim 54wherein said support further comprises an expandable proximalcircumferential portion supporting said proximal portion of said mainbody.
 56. The branching endoluminal prosthesis of claim 54 furthercomprising an attachment mechanism which couples said distal support tosaid distal portion of said main body of said liner.
 57. The branchingendoluminal prosthesis of claim 56 wherein said attachment mechanismattaches said first lobe and a portion of each indentation to the firstbranch.
 58. The branching endoluminal prosthesis of claim 57 whereinsaid attachment mechanism attaches said second lobe and a portion ofeach indentation to the second branch.